Variable duration flectric timer with adjustable contacts



Dec. 19, 1967 0. w. HENDRY VARIABLE DURATION ELECTRIC TIMER WITH ADJUSTABLE CONTACTS 2 Sheets-Sheet 1 Filed Sept. 28, 1965 INVENTOR. DAV/D W. HNDRY BY 56% 4754 ATTOKNE vs Dec. 19, 1967 D. w. HENDRY 3,359,382

VARIABLE DURATION ELECTRIC TIMER WITH ADJUSTABLE CONTACTS Filed Sept. 28, 1965 2 Sheets-Sheet 2 ill F I E:- .4-

67 73 ?//Z/& //////1 2/ FIE--5- INVENTOR. 'DAV/D W HENDRY BY 5M ATTORNEYS United States Patent 3,359,382 VARIABLE DURATIGN ELECTRIC TIMER WITH ADJUSTABLE CONTACTS David W. Hendry, 215 Crocker Ave., Piedmont, Calif. 94611 Filed Sept. 28, 1965, Ser. No. 490,946 16 Ciaims. (Cl. 200-67) ABSTRACT OF THE DISCLOSURE A variable duration timer especially adapted for controlling multi-valve irrigation systems having electrically controlled valves with the timer being constructed with a clock mechanism adapted to initiate selected cycles of operation, and with each cycle of operation providing energy for a plurality of electrically controlled valves through a rotary switch contact designed to operate the rotary switch a given cycle upon activation; said rotary switch being characterized by having a brush trace a circular path and contact a plurality of radially mounted brushes which are accurately adjusted through radial movement across said circular path and present tapered ends of variable width, depending upon the radial positioning, with each contact being operated by a dial operatively connected thereto through rack and pinion gears, and an electrical drive for the rotary switch capable of providing a fast drive between contact points and the slow drive over the switch contacts for rapid and efficient completion of the operative cycle.

The present invention relates to an adjustable timer, and more particularly to an adjustable timer suitable for controlling mul-ti-valve irrigation systems having electrically controlled valves.

Clock-operated timers are known for use in turning sprinklers on and off. An example of such a timer is shown in United States Patent 2,745,918 and this patented unit has been particularly valuable for giving automatic control in a sprinkler system. Yet where a plurality of sprinklers or sprinkler systems were to be operated on different schedules, it was necessary to use a plurality of timers of the above type.

Another example of a timer used for controlling irrigating systems is that disclosed in my United States Patent No. 3,188,503, issued June 8, 1965, entitled, Adjustable Timer. The present invention is an improvement of the adjustable timer disclosed in my above-mentioned patent and among the several objects of the invention may be noted the provision of an improved timer which will turn on and off a plurality of valves according to a timed program both as to activation and duration of the period of each valve. Considerable flexibility is obtained by suitable controls which allow the timer to be set so as to vary any of these criteria as desired.

Accordingly, it is a primary object of this invention to provide an improved timer of the above character capable of being set to any of various programs which can operate a number of sprinklers independently of each other for predetermined periods of time.

Another object of this invention is to provide an improved timer suitable for automatic control of irrigation systems which can operate substantially continuously on repeated cycles according to a predetermined program.

A still further object is to provide an improved timer of the class described wherein the length of each of the periods during which sprinkling or watering is provided may be conveniently varied.

Still another object of this invention is to provide an improved timer of the class described which is immedi ately responsive to its set-ting whereby small periods as well as large periods may be accurately controlled and sprinkling times as short or as long as is necessary may be accurately provided.

Yet another object of this invention is to provide a timer of the character described that is simple in construction, efficient in operation, capable of long, accurate service, easy to assemble, and effective in its control.

Further objects and advantages of my invention will become apparent as the specification proceeds, and the new and useful features of my invention Will be fully defined in the claims attached hereto.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated.

FIGURE 1 is a front view in elevation of the timer of this invention with a schematic showing of the control means for valves of an irrigation system;

FIGURE 2 is an enlarged fragmentary rear elevation of FIGURE 1, certain parts being removed for clarity;

FIGURE 3 is a section taken on line 33 of FIG- URE 2;

FIGURE 4 is a schematic plan view of a part of the timer illustrating the operation of the electrical circuits utilized therein; and

FIGURE 5 is an enlarged fragmentary view of FIG- URE 3.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawlngs.

Referring now to the drawings, it will be seen that the adjustable timer of the present invention generally includes a support 1, a brush 2 adapted to be connected to a source of electrical energy and supported for movement in a circular path across a plurality of contacts 3 movably mounted on the support. The contacts are connected to the valve control mechanisms of a multi-valvc irrigation system, for example, in such manner that the valve control mechanisms are actuated when the brush 2 and contacts 3 are in contact. More specifically, the support 1 includes a control panel 11 which is connected by a plurality of leads 13 to electrically-operated control mechanisms 17 for the valves of a multi-valve irrigation system, for example. It will be understood that the control mechanisms 17 may be of any well-known type, such as a solenoid-operated type for actuating a valve.

Control panel 11 is shown in FIGURES 2 and 3 to include a front control board 19, an intermediate plastic plate or other dielectric support 21, and a motor-mounting plate 23. The board 19, support 21 and plate 23 are held together by bolts 27, but are separated by spacers 29 and 31.

A shaft 33 is journaled in board 19, support 21 and motor-mounting plate 23. The rearward end of shaft 33 is connected to a motor 37, hereinafter referred to as slow motor 37, mounted on the plate 23. A gear 39 is affixed to shaft 33 and is in mesh With a gear 41 connected to a second motor 43, hereinafter referred to as fast motor 43. Slow motor 37 is adapted to drive shaft 33 at a relatively slow rotational speed, While fast motor 43 is adapted, through gears 41 and 39, to rotate the shaft at a relatively high speed. While rotation of shaft 33 by either motor 37 or 43 causes the other motor to be rotated through gears 39' and 41, the amount of such rotation is not sufiicient to damage such other motor because only one motor is energized at a time. Shaft 33 also carries two generally circular cams 49 and 51 thereon. However, cam 49 has a notch 53 in the periphery thereof, the

purpose of which will become apparent hereinafter.

Located rearwardly of support 21 and also mounted on shaft 33 is an arm 57 carrying brush 2 which is resiliently urged toward the support plate 21. It will be seen that rotation of the shaft 33 causes the brush 2 to partake of a circular path against support plate 21. A

knob 61 on the forward end of shaft 33 is provided to permit manual rotation of the shaft 33.

As clearly shown in FIGURE 2, support plate 21 is provided with a plurality of elongated slots 63 spaced circumferentially around the shaft 33 and extending radially with respect thereto. A contact carrier 67, constructed of wood, for example, is mounted in each of the slots 63. The contact carriers 67 are generally T-shaped in lateral cross-section and extend forwardly from the slots 63 and support plate 21 to the rearward side of control board 19. Each contact carrier 67 carries a contact 3 on its rearward side and adjacent the generally fiat and rearward face of support plate 21. Contacts 3 may be formed of a suitable electrically-conductive material, such as copper, for example, in the shape of an elongate plate 69 having a generally rectangular cross-section. Each contact 3 is tapered, as indicated at 71, so that by moving the contacts radially toward or away from the shaft 33, a face of varying width is presented to the path of brush 2. As will be apparent, the length of time with which the brush 2 is in contact with any particular contact plate 69 is dependent upon the position of the plate relative to the path of the brush.

The means for moving each contact plate 69 radially toward and away from shaft 33 includes a rack 73 formed on one side of each contact carrier 67 and a pinion 77 on a shaft 79 extending through control panel 19. A turning knob 81 is connected to the forward end of shaft 79 for turning the respective pinion. It will thus be seen that the rotation of any particular turning knob 81 causes the respective contact carrier 67 and its associated contact plate 69 to be moved either radially toward or radially away from the shaft 33, thus varying the width of the contact plate which is presented to the path of brush 2.

An electrically-conductive arm 83 is connected to mounting plate 23 and has a sliding contact 87 at one end thereof in constant contact with cam 51. A switch 89 is also secured to plate 23 and has an arm 91, the outer end of which is adapted to ride on cam 49. Switch 89 is normally closed, but when the outer end of arm 91 drops into notch 53, the switch 89 is opened. The purposes of switch 39 and the arm 83 with its sliding contact 87 will become apparent when the circuitry of the apparatus is described. 1

The apparatus of this invention may be manually controlled or, if desired, a clock 93 may be connected to control board 19 for controlling the overall operation of the apparatus. The clock 93 may be any timer clockequipped to drive a switch and may be of any desired duration. In a preferred form of the invention, a 24-hour clock is used so as to provide irrigation timed on a daily basis. In addition, a daily indexing wheel 97 may be provided so that the system will only be operated on certain days. Such daily indexing wheels and clocks are well known. Such clocks are adapted to close a normally open switch 99'when it is desired to start an irrigating operation. Before the irrigating operation is completed, however, the switch 99 is again opened.

The electrical circuit used for the apparatus of this invention is shown in FIGURE 4 to include a pair of lines 111 and 113 adapted to be connected to a power source. As used herein, the term line means any electrical connection between two points. Line 113 includes a manually-operable switch 117 and a fuse 119. Clock 93 is connected between lines 111 and 113 and runs continuously when switch 117 is closed.

A line 121 extends between one side or terminal of switch 89 and line 113. A line 123 extends between the other side or terminal of switch 89 and one terminal of normally open switch 99. A line 127 extends between line 123 and one terminal of fast motor 43. The other terminal of fast motor 43 is connected by line 129 to one pole of a relay switch 131. A line 133 connects one terrninal of slow motor 37 to line 121. The other terminal of slow motor 37 is connected by a line 137 to the other pole of switch 131. A switch arm 139 of switch 131 is connected to line 111 and is adapted to be moved back and forth between the poles connected to lines 129 and 137, respectively, depending upon the energization of the relay 141 of switch 131. The relay 141 is adapted to be energized in a circuit which receives its power from the main circuit through a transformer 143. It is desirable to operate the brush 2 and elongate contact plate 69 portion of the circuitry on a relatively low voltage to prevent rapid deterioration of the parts due to sparking. Accordingly, the circuit containing the relay 141, brush 2 and elongate contact plate 69 may be made to operate on 24 volts, for example, while the main circuit which powers motors 43 and 37 may operate on volts, for example.

One side of relay 141 is connected by a line 147 to one end of arm 83. The other side of relay 141 is connected by a line 149 through transformer 143 to the control means 17 for the valves of the irrigation system. As mentioned previously, the other sides of the control means 17 are connected by lines 13 to the individual elongate contact plates 69. 7

Assuming that brush 2. is out of contact With any of the elongate contact plates 69, switch 89 is open, switch arm 139 is in contact with the pole connected to line 129, switch 99 is open, and switch 117 is closed, operation of the apparatus is as follows:

First, the individual elongate contact plates 69 are adjusted to the desired position by rotating knobs 81 on the front control board 19. Individual dials D surrounding each knob 81 permit the elongate contact plate 69 to be adjusted so that the correct amount of watering will be provided. When the clock 93 closes normally open switch 99, a circuit is completed through lines 113 and 127, fast motor 43, line 129, switch arm 139, and line 111. Thus, fast motor 43 is energized, causing rotation of shaft 33 and brush 2. As soon as shaft 33 begins to turn, the arm of switch 89 rides out of the notch 53 and closes the switch. Thus, even though the switch 99 may open shortly after it has been closed, the circuit through fast motor 43 is maintained through line 123, switch 89 and line 121 to line 113.

As soon as the brush 2 contacts the leading edge of the first elongate contact plate 69, i.e., the physical relationship between that contact plate 69 and brush 2 changes, a circuit is completed through the particular elongate contact plate 69, line 13, the control means 17 for a particular valve in the irrigation system, line 149, relay 141, line 147, arm 83, sliding contact 87, cam 51, shaft 33, arm 57 and brush 2. Energization of relay 141 moves switch arm 139 to the pole connected to line 137. This completes a circuit from line 111 through switch arm 139, line 137, slow motor 37, line 133, line 121, and line 113. Slow motor 37 is thus energized and fast motor 43 is deenergized. Thus, the brush 2 is moved at a much slower speed across the face of the elongate contact plate 69 which is being engaged by the brush.

After the brush 2 has traveled across the face of the particular elongate contact plate being traversed, the brush 2 will snap out of engagement with the contact 69, i.e., the physical relationship between the brush and contact is again changed. This interrupts the circuit through relay 141, thus causing switch arm 139 to be moved into contact with the pole connected by line 129 to fast motor 43. Fast motor 43 is thereby energized and the switch arm 57 and brush 2 are moved quickly towards an engagement with the next succeeding elongate contact plate 69 in the path of the brush 2. When the brush 2 engages the next succeeding contact 69, the slow motor is energized in the manner previously described.

The above procedure is repeated until the switch arm 57 and brush 2 have made a complete 360 cycle around the elongate contact plate 69.

As soon as cam 51 has completed a complete 360 cycle, the switch arm 91 of switch 89 drops back in notch 53 and switch 89 is opened. This interrupts the circuit through the fast motor 43, since switch 99 is now open. Since the brush 2 is out of contact with any of the elongate contact plates 69, after 360 rotation from its initial position, i.e., the brush 2 is back in its original position, the slow motor 37 is not energized. Accordingly, the complete system is deenergized except for the clock 93 which continues to control the switch 99. When the switch 99 is closed according to the movements of clock 93, the complete operation described above is repeated.

It will be seen that the apparatus described above provides for completely automatic control of lawn sprinkling systems and the like. The adjustability of the elongate contact plates 69, including the feature of the tapering sides thereof, permits the valve controlled by that particular elongate contact plate and the brush 2 to be opened for any predetermined period of time, from a few seconds to a number of hours, depending upon the location of the elongate contact plate and the speed with which the slow motor 37 moves the brush 2 around its circular path. More or fewer watering stations may be controlled by adding or subtracting elongate contact plates 69 and the associated circuitry between the contact plates and the control means for the valves at the watering stations. While the unit has been described in connection with automatically handling a plurality of valve control means in a multivalve irrigation system, it will be understood that the timer and its associated apparatus may be used to control other like systems.

It will be understood that the slow motor 37 could be connected in the circuit in such a manner, as being connected directly between lines 111 and 123, that it would run continuously when switch 89 was closed. In such a case, an override clutch would be interposed between gear 39 and the slow motor 37 so that operation of the fast motor 43 could take place without damaging the slow motor. If the slow motor is run continuously as described, the contact members 3 act as interrupters for interrupting the operation of the fast motor 43, thus allowing the brush 2 to be rotated by the slow motor while the brush is in contact with the contact members 3. It will also be understood that, if desired, the shaft 33 could be connected to a rotary selector valve (not shown) such as described in my abovementioned patent, for controlling the operation of normally open or closed valves in the irrigation system.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. An improved timer for controlling multi-valve irrigation systems having electrically controlled valves, comprising a support, a brush adapted to be connected to a source of electrical energy and supported for movement in a circular path, a plurality of elongate contacts adapted to be individually connected to the electrically controlled valves and mounted on said support in a circumferential array with each of said contacts extending across said circular path, each of said contacts being mounted for movement across said path and having a varying width relative thereto so as to expose varying widths of said contacts to electrical current-passing engagement by said brush upon such movement across said path, timed drive means for moving said brush at controlled speeds along said circular path, and adjusting means on each contact for effecting independent movement of each contact across said path to a selected desired position for selectively controlling the duration of time said brush is in engagement with each contact.

2. A timer as described in claim 1, and wherein said drive means includes first means for moving said brush around said circular path at a predetermined constant rate of speed and second means for moving said brush along said path at a difierent constant rate of speed.

3. A timer as described in claim 1, and wherein said drive means includes first means for moving said brush around said path at a predetermined constant rate of speed in response to a predetermined physical relationship between said brush and said contacts, and second means for moving said brush along said circular path at a different constant rate of speed in response to a change in said physical relationship between said brush and said contacts.

4. A timer as described in claim 1, and wherein said drive means includes first means for moving said brush around said circular path at a predetermined constant rate of speed, and second means for moving said brush along said path at a different constant rate of speed, said first means being formed for moving said brush around said circular path at a relatively fast constant rate of speed and said second means being responsive to contact of said brush with said contacts to move said brush along said circular path at a slower constant rate of speed, thereby allowing the brush to index between successive contacts at a fast speed while slowing the speed of the brush across the contacts for extending the duration of the valve operation.

5. An improved timer for controlling multi-valve irrigation systems having electrically controlled valves, comprising a support, a brush adapted to be connected to a source of electrical energy and supported for movement in a circular path, a plurality of elongate contacts adapted to be individually connected to the electrically controlled valves and mounted on said support in a circumferential array with each of said contacts extending across said circular path, each of said contacts being mounted for movement across said path and having a varying width relative thereto so as to expose varying widths of said contacts to electrical current-passing engagement by said brush upon such movement across said path, drive means for moving said brush along said circular path, rack and pinion means for each contact for eflFecting movement thereof, and a dial associated with each of said rack and pinion means for indicating the position of the individual contacts and consequent exposure to contact by said brush.

6. A timer as defined in claim 5, and wherein each contact is secured to the respective rack and is movable therewith upon rotation of the respective pinion, a plurality of shafts journaled in said support carrying the pinions in meshing relation with said racks, and a knob on each shaft for rotating the respective pinion to advance the respective rack and contact across said circular path.

7. A timer as defined in claim 6, and wherein said racks are mounted in slots in said support around said c rcular path for guiding said racks and contacts for translational movement across the path of said brush.

8. An improved timer for controlling multi-valve irrigation systems having electrically controlled valves, comprising a support, a brush adapted to be connected to a source of electrical energy and supported for movement in a circular path, a lurality of elongate contacts adapted to be individually connected to the electrically controlled valves and radially mounted on said support in a circumferential array with each of said contacts extending across said circular path, each of said contacts being mounted for radial movement across said path and having a varying width relative thereto so as to expose varying widths of said contacts to electrical current-passing engagement by said brush upon such movement across said path, electric drive means for moving said brush along said circular path, and adjusting means on each contact for effecting independent movement of each contact across said path to desired positions for selectively controlling the duration of time said brush is in engagement with each contact, said support being substantially fiat, said elongated contacts being of generally rectangular cross-section and positioned flat against said support for 7 presenting faces to said brush which are substantially coplanar with the face of the support, and said brush having means for resiliently urging same in intimate contact with said faces.

9. An improved timer for controlling irrigation systems having a plurality of electrically operated valves, comprising a plate member of dielectric material, a brush adapted fOr connection to a source of electrical energy and supported for movement in a circular path against one side of said dielectric plate, a plurality of elongate plates of electrically conductive material adapted for individual electrical connection to said electrically operated valves and mounted on said dielectric plate in spaced circumferential array extending radially across said circular path, said elongate plates being mounted for radial movement and tapering in width so as to expose varying widths to contact by said brush upon such radial movement, electric drive means for moving said brush along said circular path at a desired rate of speed, and mechanical adjusting means on each contact for effecting independent radial movement of individual elongate plates to desired positions for individually controlling the duration of time said brush is in contact with each of said elongate plates.

10. A device as described in claim 9, and wherein said electric drive means includes a slow motor for moving said brush around said circular path at a predetermined constant rate of speed and is energized by contact of said brush with said elongated plates to move said brush along said circular path at a different constant rate of speed.

11. A device as described in claim 9, and wherein said electric drive means includes a fast motor for moving said brush around said circular path at a relatively fast constant rate of speed and is energized when the brush is out of contact with said elongated plates, and a slow motor energized when the brush is in contact with said elongate plates to move said brush along said circular path at a slower constant rate of speed, thereby allowing the brush to index between successive elongate plates at a relatively high speed allowing the brush to move across the elongate plates at a relatively slow speed for extending the duration of the valve operation.

12. An improved timer for controlling irrigation systems having a plurality of electrically operated valves, comprising a plate member of dielectric material, a brush adapted for connection to a source of electrical energy and supported for movement in a circular path against one side of said dielectric plate, a plurality of elongate plates of electrically conductive material adapted for individual electrical connection to said electrically operated valves and mounted on said dielectric plate in spaced circumferential array extending radially across said circular path, said elongate plates being mounted for radial movement and tapering in width so as to expose varying widths to contact by said brush upon such radial movement, drive means for moving said brush along said circular path at a desired rate of speed, rack and pinion means for each elongate plate for effecting said radial movement, and a dial associated with each of said rack and pinion means for indicating the radial position of the individual plates and consequent exposure to contact by said brush.

13. A device as defined in claim 12, and wherein each elongate plate is secured to the respective rack and movable therewith upon rotation of the respective pinion, a plurality of shafts journaled in said dielectric plate carrying the pinions in meshing relation with said racks, and a knob on each shaft for rotating the respective pinion to advance the respective rack and elongate plate across said circular path.

14. The device as-defined in claim 13, and wherein said racks are mounted in radial slots in the dielectric plate around said circular path for guiding said racks and elongate plates for translational movement across the path of said brush.

15. An improved timer for controlling irrigation systems havinga plurality of electrically operated valves, comprising a plate member of dielectric material, a brush adapted for. connection to a source of electrical energy and supported for movement in a circular path against one side of said dielectric plate, a plurality of elongate plates of electrically conductive material adapted for individual electrical connection to said electrically operated valves and mounted on said dielectric plate in spaced circumferential array extending radially across said circular ath, said elongate plates being mounted for radial movement and tapering in width so as to expose varying widths to contact by said brush upon such radial movement, electrically operated drive means for moving said brush along said circular path at a desired rate of speed, a'switch element mounted for rotation with said brush for energizing the drive through a complete revolution of said brush and providing a shut-off position at the end of the cycle thereof, a time clock for providing energy to start the electrically operated drive means and close the switch element, adjusting means for effecting radial movement of individual elongate plates to desired positions for individually controlling the duration of time said brush is in contact with each of said elongate plates, said elongate plates being of generally rectangular cross-section and positioned flat against said dielectric plate for presenting faces substantially co-planar with the face of the dielectric plate to the brush, and said brush having means for resiliently urging the brush into intimate contact with said faces.

16. An improved timer for controlling multi-valve irrigation systems having a plurality of valves comprising a support, a brush adapted to be connected to a source of electrical energy and supported for movement in a circular path, a plurality of elongated contacts mounted on said support in a circumferential array with each of said contacts extending across said circular path, each of said contacts being mounted for movement across said path and having a varying width relative thereto so as to expose .varying Widths of said contacts to electrical current-passing engagement by said brush upon such movement across said path, electrically operated drive means for moving said brush along said circular path, a switch element mounted for rotation with said brush for energizing the drive through a complete revolution of said brush and providing a shut-oft" position at the end of the cycle thereof, a time clock for providing energy to start the electrically operated drive means and close the switch element, and adjusting means for effecting movement of each contact across said path to desired positions for selectively controlling the duration of time said brush is in engagement with each contact for controlling the duration of operation of each of the valves of the system.

References Cited UNITED STATES PATENTS 2,784,266 3/ 1957 Krahulec 20025 2,921,995 1/1960 Carlson et al. 200-10 3,151,257 9/1964 Anderson 307-14l.4

BERNARD A. GILHEANY, Primary Examiner.

H. E. SPRINGBORN, As is a t Ex miner. 

1. AN IMPROVED TIMER FOR CONTROLLING MULTI-VALVE IRRIGATION SYSTEMS HAVING ELECTRICALLY CONTROLLED VALVES, COMPRISING A SUPPORT, A BRUSH ADAPTED TO BE CONNECTED TO A SOURCE OF ELECTRICAL ENERGY AND SUPPORTED FOR MOVEMENT IN A CIRCULAR PATH, A PLURALITY OF ELONGATE CONTACTS ADAPTED TO BE INDIVIDUALLY CONNECTED TO THE ELECTRICALLY CONTROLLED VALVES AND MOUNTED ON SAID SUPPORT IN A CIRCUMFERENTIAL ARRAY WITH EACH OF SAID CONTACTS EXTENDING ACROSS SAID CIRCULAR PATH, EACH OF SAID CONTACTS BEING MOUNTED FOR MOVEMENT ACROSS SAID PATH AND HAVING A VARYING WIDTH RELATIVE THERETO SO AS TO EXPOSE VARYING WIDTHS OF SAID CONTACTS TO ELECTRICAL CURRENT-PASSING ENGAGEMENT BY SAID BRUSH UPON SUCH MOVEMENT ACROSS SAID PATH, TIMED DRIVE MEANS FOR MOVING SAID BRUSH AT CONTROLLED SPEEDS ALONG SAID CIRCULAR PATH, AND ADJUSTING MEANS ON EACH CONTACT FOR EFFECTING INDEPENDENT MOVEMENT OF EACH CONTACT ACROSS SAID PATH TO A SELECTED DESIRED POSITION FOR SELECTIVELY CONTROLLING THE DURATION OF TIME SAID BRUSH IS IN ENGAGEMENT WITH EACH CONTACT. 